<p>You can back out of the ED agreement if the school turns out to be unaffordable. You cannot, however, compare financial aid offers to that of the ED school - you can reject the ED offer based on insufficient aid, but not “take it back” once RD decisions are available. You have some time to educate yourself on the costs/benefits of applying ED. You would not be the first one to apply ED for the boost it gives in admissions, and I think that can be the right strategy for some. </p>